chem test energy and chemical change

energy

the ability to do work or produce heat. exists in potential and kinetic energy

law of conservation of energy

any chemical reaction or physical process, energy is neither created nor destroyed

chemical potential energy

energy stored in a substance because of its composition. plays an important role in chemical reactions

heat (q)

energy that is in the process of flowing from a warmer object to a cooler object

calorie (cal)

the amount of energy required to raise the temp of one gram of pure water by one degree celsius

joule

the SI unit of heat and energy

specific heat

the amount of heat required to raise the temp of one gram of that substance by one degree celsius

calorimeter

an insulated device used for measuring the amount of heat absorbed or released during a chemical or physical process

thermochemistry

the study of heat changes that accompany chemical reactions and phase changes

system

the specific part of the universe that contains the reaction or process you wish to study

surroundings

everything in the universe other than the system

universe

the system plus the surroundings

enthalpy (H)

the heat content of a system at constant pressure

enthalpy (heat of reaction)

the change in the enthalpy for a reaction

thermochemical equation

a balanced chemical equation that includes the physical states of all reactants and products and the energy change

enthalpy (heat) of combustion

the enthalpy change for the complete burning of one mole of the substance

molar enthalpy (heat) of vaporization

the heat required to vaporize one mole of a liquid

molar enthalpy (heat) of fusion

the heat required to melt one mole of a solid

Hess’s law

if you can add two or more thermochemical equations to produce a final equation for a reaction, then the sum of the enthalpy changes for the individual reactions is the enthalpy change for the final reaction

standard enthalpy (heat) of formation

the change in enthalpy that accompanies the formation of one mole of the compound in its standard state from its elements in their standard states

spontaneous process

any physical or chemical change that, once begun, occurs with no outside intervention

entropy

a measure of the number of possible ways that the energy in a system can be distributed related to the freedom of the system’s particles

2nd law of thermodynamics

spontaneous processes always proceed in such a way that the entropy of the universe increases

gibb’s free energy

the energy that is available to do work.